Electronic endoscope system

ABSTRACT

In an electronic endoscope system, an RF signal is produced through quadrature modulation of a picture signal that is representative of an image taken through an electronic endoscope. When control signals are entered by an operator through a control section of the electronic endoscope, a data superimposing section superimposes the entered control signals on the RF signal in horizontal scanning intervals within a vertical blanking interval. The RF signal having the control signals superimposed thereon is sent as an electric wave of a single frequency band to a processor. In the processor, a data analyzer carries out sampling to extract the entered control signals if they are superimposed on the picture signal, and analyzes the contents of the entered control signals. Based on the results of analysis, a CPU controls respective components of the signal processor.

FIELD OF THE INVENTION

The present invention relates to an electronic endoscope systemconsisting of an electronic endoscope and a processor, which communicatesignals to each other using electric waves.

BACKGROUND OF THE INVENTION

Medical diagnoses utilizing an electronic endoscope have widely beenpracticed in the medical field these days. The electronic endoscope hasan imaging device like a CCD, which is built in an end of an elongatedprobing portion that is introduced into a body cavity, so that the CCDtakes an image signal from an internal body site. The image signal isprocessed in a processor, to display an image of the internal body site,called an endoscopic image, on a monitor.

The electronic endoscope and the processor are usually connected to eachother through a signal cable. Also, wireless electronic endoscopessystems have been suggested, for example, in Japanese Laid-open PatentApplication Nos. Sho 60-48011 and 2001-046334. In the wirelesselectronic endoscope system, the electronic endoscope is provided with amodulator and a sender for sending the modulated signal as an electricwave, whereas the processor is provided with a receiver for receivingthe electric wave and a demodulator for demodulating the modulatedsignal. Because the signal is communicated by way of the electric wave,the signal cable is unnecessary, so the handling of the wirelesselectronic endoscope is superior to those using the signal cable.

In addition to the above-mentioned advantage that the signal cable doesnot give limit to the handling of the electronic endoscope, and thus theworkability is improved, the wireless electronic endoscope system hasanother advantage. Since there is not any electric connection betweenthe electronic endoscope and the processor, it is unnecessary tomaintain a high dielectric strength voltage of about 4 kV between apatient circuit and a secondary circuit, while such a high dielectricstrength voltage is necessary for the conventional electronic endoscopesystem using the signal cable.

The electronic endoscope is also provided with many kinds of controlswitches, including a freeze switch for capturing a still image from anendoscopic image, and a movie-recording switch for recording motionpictures of the body site.

In the conventional wireless electronic endoscope, control signalsentered through the control switches are sent to the processor using anelectric wave of a different frequency band from the electric wave forsending the endoscopic image. In practice, it is usual to install anumber of electronic endoscope systems together in a specific treatmentroom in a hospital. Therefore, if an individual electronic endoscopesystem occupies many working frequency bands, interference can occurbetween the equipments. To avoid the interference, the number of systemsallowed to install in the same room is limited.

SUMMARY OF THE INVENTION

In view of the foregoing, a primary object of the present invention isto provide a wireless electronic endoscope system whose occupiedfrequency bandwidth is reduced to the minimum, so it permits installinga larger number of these systems in the same place.

To achieve the above and other objects, in an electronic endoscopesystem of the present invention, which comprises an electronic endoscopehaving an imaging device for obtaining an image signal from a site toobserve inside a body cavity, and a processor for producing an image ofthe site to observe based on an electric wave received from theelectronic endoscope, the electronic endoscope comprises a modulator forproducing a radio frequency signal through quadrature modulation of apicture signal that is obtained by digitalizing the image signal; acontrol section manually operated to enter control signals; a datasuperimposing device for superimposing the entered control signals onthe radio frequency signal in horizontal scanning intervals within avertical blanking interval of the radio frequency signal; and a senderfor sending the radio frequency signal as the electric wave to theprocessor, after the control signals are superimposed on the radiofrequency signal; and the processor comprises a receiver for receivingthe radio frequency signal as the electric wave from the electronicendoscope; a demodulator for demodulating the radio frequency signalinto the picture signal; a data analyzer for sampling the enteredcontrol signals if they are superimposed on the radio frequency signal,and analyzing contents of the entered control signals; and a controllerfor controlling corresponding components based on results of analysis bythe data analyzer.

According to a preferred embodiment, the data superimposing devicesuperimposes the entered control signal at a predetermined time intervalfrom the start of the vertical blanking interval, whereas the dataanalyzer carries out the sampling only when it detects the predeterminedtime interval.

Since the control signals entered through the control section aresuperimposed on the picture signal, and are sent together to theprocessor as the electric wave of the same frequency band, theelectronic endoscope system of the present invention needs to occupy asingle channel of frequency band. Consequently, it is possible to raisethe number of endoscope systems installable in the same place withoutthe risk of interference between the systems.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects and advantages of the present invention willbe more apparent from the following detailed description of thepreferred embodiments when read in connection with the accompanieddrawings, wherein like reference numerals designate like orcorresponding parts throughout the several views, and wherein:

FIG. 1 is a schematic diagram illustrating an electronic endoscopesystem consisting of an electronic endoscope and a processor;

FIG. 2 is a block diagram illustrating an internal structure of theelectronic endoscope;

FIG. 3 is a block diagram illustrating an internal structure of a datasuperimposing section;

FIG. 4 is a timing chart illustrating wave forms of signals output fromrespective components of the data superimposing section; and

FIG. 5 is a block diagram illustrating an internal structure of theprocessor.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a wireless electronic endoscope system 2, which consists ofan electronic endoscope 10 and a processor 11, which communicatessignals to each other by way of electric wave 12.

The electronic endoscope 10 is provided with a probing portion 13 thatis introduced into a body cavity, and a control section 14 that isjoined to a base end of the probing section 13. Built in a tip portion13 a, which is joined to a distal end of the probing section 13, are anobjective lens 15 for forming an optical image of an internal body partto be observed, a CCD 16 as an imaging device for capturing the opticalimage of the internal body part, an illuminative lens 17, and an LEDlight source 18 for illuminating the body cavity, see FIG. 2. The imagecaptured through the CCD 16 is sent to the processor 11, and isdisplayed as an endoscopic image on a monitor 19 that is connected tothe processor 11.

Behind the tip portion 13 a is provided a curving section 20 consistingof a number of linked curving segments. By operating an angle knob 14 aon the control section 14, a number of wires, which are not shown butextend in the probing section 13, are pulled and pushed to curve thecurving section 20 appropriately, thereby to direct the tip portion 13 ato an aimed point inside the body cavity.

A cartridge 23, in which a water tank 21 containing water and an aircylinder 22 containing air are built, is detachably attached to a bottomposition of the control section 14. In cooperation with an action on awatering/airing switch 14 b of the control section 14, the watercontained in the water tank 21 and the air contained in the air cylinderare fed through a water pipe and an air pipe and ejected from a washnozzle toward the objective lens 15, though the water pipe and the airpipe are not shown but disposed in the electronic endoscope 10, and thewash nozzle is not shown but formed through the tip portion 13 a.Thereby, dirt on the surface of the objective lens 15 is washed away,and the air is sent to the body cavity. The cartridge 23 is sopositioned that the wrist of the operator is held on the cartridge 23 tostabilize the electronic endoscope 10 on operating it. Designated by 24is an inlet for inserting a treatment tool.

Beside the angle knob 14 a and the watering/airing switch 14 b, thecontrol section 14 is provided with a freeze switch 14 c, a releaseswitch 14 d, a zooming switch 14 e, a movie recording switch 14 f and aprint switch 14 g. The freeze switch 14 c is operated to capture a stillimage from the endoscopic image. The release switch 14 d is operated torecord the still image on a not-shown recording medium like a memorycard. The zooming switch 14 e is operated to change magnification of theendoscopic image. The movie recording switch 14 f is operated to recordthe endoscopic image as moving images in a not-shown movie recorder. Theprint switch 14 f is operated to print out a hard copy of the stillimage through a not-shown printer.

Referring to FIG. 2, the overall operation of the electronic endoscope10 is under the control of a CPU 30. The control section 14 and a ROM 31storing various programs and data for controlling the operation of theelectronic endoscope 10 are connected to the CPU 30. The CPU 30 readsout necessary program and data from the ROM 31 and writes them on anot-shown RAM that is built in the CPU 30, to control the operation ofthe electronic endoscope 10 based on the read program and data.

The CPU 30 adds to a control signal, which is entered through one of theswitches 14 c to 14 g of the control section 14, a start code, an endcode, a checksum, data of the switch operated to enter the controlsignal, and data of operational conditions of the switches, such asON/OFF or continuous pressing of the switches. Thereafter, the CPU 30outputs the control signal to a data superimposing section 35. Detailsof the data superimposing section 35 will be described later.

A driver 32 is connected to the LED 18. The driver 32 turns the LED 18on and off under the control of the CPU 30. The light emitted from theLED 18 is projected through the illuminative lens 17 onto the internalbody part to observe. Note that the LED 18 is not necessarily located inthe tip portion 13 a, but may be located in an intermediate portioninside the control section 14. In that case, the light from the LED 18is guided through a light guide to the tip portion 13 a.

The objective lens 15 forms an optical image of the internal body parton an imaging surface of the CCD 16, so the CCD 16 outputs fromindividual pixels analog image signals corresponding to the opticalimage. The analog image signals are fed to an AFE (analog front end)circuit 33, where the analog image signal are subjected to correlateddouble sampling, and are amplified and converted into a digital picturesignal. The digital picture signal is subjected to digital quadraturemodulation in a modulator 34, to produce a radio frequency (RF) signal.

In the data superimposing section 35, the entered control signal, asbeing attached by the various data, is superimposed on the radiofrequency signal in a horizontal scanning interval Th within a verticalblanking interval Tb1, as set forth in detail with reference to FIG.4.As shown in FIG.3, the data superimposing section 35 is provided with aclamp circuit 50, a synch separation circuit 51, a vertical synchseparation circuit 52, a phase locked loop (PLL) 53, a timing generator(TG) 54, a memory 55, a level converter circuit 56 and a superimposingcircuit 57.

The clamp circuit 50 is AC-coupled to the modulator 34, to output asignal S1 that reproduces a DC component of the RF signal as producedfrom the modulator 34. The synch separation circuit 51 eliminates thepicture signal components from the signal S1 to output a synchronizingsignal S2. The vertical synch separation circuit 52 takes out a verticalsynchronizing signal S3 from the synchronizing signal S2, and outputsthe signal S3 to the timing generator 54.

The PLL 53 takes out a horizontal synchronizing signal S4 from thesynchronizing signal S2, and outputs the signal S4 to the timinggenerator 54. The PLL 53 also generates a high frequency clock signal tothe timing generator 54. The high frequency clock signal is phase-lockedat an integral multiple of the horizontal scanning interval, and definestiming of picking up the entered control signals, which are enteredthrough the control section 14, into the memory 55.

Based on the vertical and horizontal synchronizing signals S3 and S4 andthe clock signal, the timing generator 54 generates a memory controlsignal and sends it to the memory 55. The memory control signal definesread-write timing of the entered control signals, and memory addressesof them. The timing generator 54 also generates a superimpose timingsignal S6 and sends it to the superimposing circuit 57, for definingtiming of superimposing the entered control signal on the radiofrequency signal in the superimposing circuit 57.

At the timing defined by the memory control signal from the timinggenerator 54, the memory 55 reads out the entered control signals, whichare entered through the switches 14 c to 14 g of the control section 14,from the CPU 30, and memorizes the entered control signals. At the sametime, the memory 55 outputs the entered control signals to the levelconversion circuit 56. The level conversion circuit 56 converts thelevel of the entered control signals to be suitable for superimposingthem on the signal S1 that is output from the clamp circuit 50.

The superimposing circuit 57 superimposes the entered control signals,whose level are converted through the level conversion circuit 56, onthe output signal S1 of the clamp circuit 50 at the timing defined bythe superimpose timing signal S5 from the timing generator 54, therebyto generate a radio frequency (RF) signal S6. Concretely, the enteredcontrol signals are superimposed on the output signal S1 after apredetermined time interval T2 from the start of the vertical blankinginterval Tb1. For example, the time interval T2 is four times thehorizontal scanning interval Th. Finally, the radio frequency signal S6is sent as the electric wave 12.

Note that FIG.4 shows examples of signal wave forms around the verticalblanking interval Tb1 from an end of an even filed to a start of an oddfield. Designated by Pe is a horizontal scanning picture signal of theeven field, and Po is a horizontal scanning picture signal of the oddfield. Tv designates the vertical synchronizing interval. Da, Db and Dcrepresent the entered control signals as superimposed in thesuperimposing circuit 57. These signals can include data of at most 20bits individually.

Referring back to FIG.2, the sender section 36 sends the radio frequencysignal S6 as the electric wave 12 through an antenna 37 to the processor11. While none of the switches 14 c to 14 g of the control section 14 isoperated, the data superimposing section 35 does not work, so the signalS1 is directly fed to the sender section 36.

The connector 38 is connected to batteries, e.g. serial connected twonickel-hydride batteries having a normal voltage of 1.2V. The electricpower from the batteries 39 is supplied through a power supply section40 to the respective components of the electronic endoscope 10 under thecontrol of the CPU 30. Although it is omitted from the drawings, abattery chamber for containing the batteries 39 is formed behind thecontrol section 14, and the connector 38 is located inside the batterychamber.

FIG.5 shows the structure of the processor 11, wherein a CPU 60 controlsoverall operations of the processor 11. The CPU 60 is connected to a ROM61 that stores various programs and data for controlling the operationsof the processor 11. The CPU 60 reads out necessary ones of theseprograms and data from the ROM 61, writes them on a not-shown built-inRAM, and controls the operation of the processor 11 based on the readprogram and data.

An antenna 62 receives the electric wave 12 from the electronicendoscope 10. A receiver section 63 amplifies the electric wave 12 asreceived on the antenna 62, i.e. the radio frequency signal. Ademodulator 64 demodulates the original picture signal before beingmodulated in the electronic endoscope 10, for example, by subjecting theradio frequency signal to digital quadrature detection.

Under the control of the CPU 60, a synch separating section 65 carriesout amplitude separation to separate a synchronizing signal from thepicture signal as demodulated in the demodulator 64. Thereafter, thesynch separating section 65 carries out frequency separation forseparating the horizontal synchronizing signal and the verticalsynchronizing signal. A video signal producer 66 produces a digitalvideo signal from the picture signal. A image processor 67 treats thevideo signal, as produced from the video signal producer 66, withvarious image-processing, such as masking and character data attaching.A buffer 68 temporarily stores the video signal as processed in theimage processor 67, and the video signal is used for displaying anendoscopic image on the monitor 19.

A data analyzer 69 executes a sampling process to check if there are anyentered control signals superimposed on the picture signal demodulatedin the demodulator 64. Specifically, the data analyzer 69 executes thesampling only when it detects the predetermined time interval T2 fromthe start of the vertical blanking interval Tb1, provided forsuperimposing the entered control signals.

If there are entered control signals superimposed on the picture signal,the data analyzer 69 takes out the entered control signals from thepicture signal to analyze the contents, and sends the results ofanalysis to the CPU 60. Based on the results of analysis by the dataanalyzer 69, the CPU 60 controls the operation of the respectivecomponents associated with the entered control signals. For example, ifthe results of analysis show that the freeze switch 14 c has beenoperated, the CPU 60 controls the image processor 67 to stop writingdata on the buffer 68. Then, a frozen image is displayed on the monitor19.

To observe a body cavity with the electronic endoscope system 2, firstthe LED light source 18 is turned on, and the probing section 13 isintroduced into the body cavity, to take endoscopic images through theCCD 16 while illuminating the inside of the body cavity. The takenendoscopic images are observable on the monitor 19.

Concretely, an optical image of a body part inside the body cavity isformed on the imaging surface of the CCD 16 through the objective lens15, so the CCD 16 outputs image signals corresponding to the opticalimage. The analog image signals are subjected tocorrelated-double-sampling, and are amplified and converted into adigital picture signal at the AFE 33.

The modulator 34 subjects the digital picture signal to digitalquadrature modulation, to produce a radio frequency (RF) signal. Theradio frequency signal is amplified at the sender section 36, and thensent as the electric wave 12 from the antenna 37.

On the other hand, the electric wave 12 from the antenna 37 is receivedat the antenna 62 of the processor 11, and is amplified as the radiofrequency signal in the receiver section 63. The demodulator 64 subjectsthe amplified radio frequency signal to digital quadrature detection, todemodulate the original picture signal before being modulated in theelectronic endoscope 10.

The demodulated picture signal is subjected to synch separationprocesses in the synch separating section 65 under the control of theCPU 60. The video signal producer 66 produces a digital video signalfrom the picture signal. The video signal is subjected to variousimage-processing in the image processor 67. The processed vide signal isstored temporarily in the buffer 68, and is displayed as the endoscopicimages on the monitor 19.

Next, a processing sequence executed in response to the operation on oneof the switches 14 c to 14 g of the control section 14 will bedescribed.

When one of the switches 14 c to 14 g is operated, a correspondingcontrol signal is entered. Then, the CPU 30 adds to the entered controlsignal a start code, an end code, a checksum, data showing what kind ofswitch is operated, data showing the switching conditions of theoperated switch. The entered control signal with the additional codesand data is sent the data superimposing section 35.

In the data superimposing section 35, the clamp circuit 34 reproducesthe DC component of the picture signal as modulated at the modulator 34,and outputs the DC component as the signal Si. The synch separationcircuit 51 eliminates the picture signal components from the signal S1to output the synchronizing signal S2. The vertical synch separationcircuit 52 takes out the vertical synchronizing signal S3 from thesynchronizing signal S2, and outputs the signal S3 to the timinggenerator 54.

The PLL 53 takes out the horizontal synchronizing signal S4 from thesynchronizing signal S2, and outputs the signal S4 to the timinggenerator 54. The PLL 53 also generates the high frequency clock signal,which is phase-locked at an integral multiple of the horizontal scanninginterval, and defines timing of picking up the entered control signalsinto the memory 55. The high frequency clock signal is output to thetiming generator 54.

Based on the vertical and horizontal synchronizing signals S3 and S4 andthe clock signal, the timing generator 54 generates the memory controlsignal for controlling the memory 55 and the superimpose timing signalS6 for controlling the superimposing circuit 57, and sends them to thememory 55 and the superimposing circuit 57, respectively.

The entered control signal, to which the CPU 30 attaches the additionaldata, is read in the memory 55 at the timing defined by the memorycontrol signal, and is output to the level conversion circuit 56. Thelevel conversion circuit 56 converts the level of the entered controlsignal to be suitable for superimposing it on the signal S1 that isoutput from the clamp circuit 50.

The level conversion circuit 56 outputs the entered control signal tothe superimposing circuit 57, so the superimposing circuit 57superimposes the entered control signal on the output signal Si of theclamp circuit 50, at the timing defined by the superimpose timing signalS5 that is generated from the timing generator 54, i.e., at thepredetermined time interval T2 from the start of the vertical blankinginterval Tb1. The subsequent radio frequency signal S6 is fed to thesender section 36, and is sent as the electric wave 12 from the antenna37 to the processor 11.

When the radio frequency signal S6 is received on the receiver section63, and is demodulated into the picture signal in the demodulator 64,the data analyzer 69 takes out the entered control signal from thepicture signal, analyzes the contents of the entered control signal, andoutputs the results of analysis to the CPU 60. Based on the results ofanalysis, the CPU 60 controls the operations of the respectivecomponents corresponding to the entered control signals. Thus, both thepicture signal for reproducing the endoscopic image and the controlsignals entered through the switches 14 c to 14 g of the control section14 are sent to the processor 11 on the electric wave 12 of the samefrequency band. So the electronic endoscope system of the presentinvention occupies a single channel of a frequency bandwidth.Consequently, it is possible to raise the number of endoscope systemsinstallable in the same place.

Furthermore, since the data superimposing section 35 superimposes theentered control signals on the radio frequency signal, which is producedby quadrature modulation of the picture signal, at the predeterminedtime interval T2 from the start of the vertical blanking interval Tb1,the data analyzer 69 can carry out the sampling process for checking ifany entered control signals are superimposed on the picture signal, onlywhen it detects the predetermined time interval T2. So the processingtime is saved in the data analyzer 69.

Although the present invention has been described with respect to thepreferred embodiment having the data superimposing section 35, thepresent invention is not to be limited to the above embodiment. On thecontrary, various modifications will be possible without departing fromthe scope of claims appended hereto.

1. An electronic endoscope system comprising an electronic endoscopehaving an imaging device for obtaining an image signal from a site toobserve inside a body cavity, and a processor for producing an image ofthe site to observe based on an electric wave received from saidelectronic endoscope, wherein said electronic endoscope comprises: amodulator for producing a radio frequency signal through quadraturemodulation of a picture signal that is obtained by digitalizing theimage signal; a control section manually operated to enter controlsignals; a data superimposing device for superimposing the enteredcontrol signals on the radio frequency signal in horizontal scanningintervals within a vertical blanking interval of the radio frequencysignal; and a sender for sending the radio frequency signal as theelectric wave to said processor, after the control signals aresuperimposed on the radio frequency signal; and wherein said processorcomprises: a receiver for receiving the radio frequency signal as theelectric wave from said electronic endoscope; a demodulator fordemodulating the radio frequency signal into the picture signal; a dataanalyzer for sampling the entered control signals if they aresuperimposed on the radio frequency signal, and analyzing contents ofthe entered control signals; and a controller for controllingcorresponding components based on results of analysis by said dataanalyzer.
 2. An electronic endoscope system as claimed in claim 1,wherein said data superimposing device superimposes the entered controlsignal at a predetermined time interval from the start of the verticalblanking interval, whereas said data analyzer carries out the samplingonly when it detects the predetermined time interval.
 3. An electronicendoscope system as claimed in claim 1, wherein said control sectioncomprises at least one of a freeze switch, a release switch, a zoomingswitch, a movie recording switch and a print switch, wherein said freezeswitch is operated to capture a still image of the site to observe, saidrelease switch is operated to record the still image, said zoomingswitch is operated to change magnification of the image of the site toobserve, said movie recording switch is operated to record moving imagesof the site to observe, and said print switch is operated to print out ahard copy of an image of the site to observe.
 4. An electronic endoscopesystem as claimed in claim 1, wherein said data superimposing devicecomprises a clamp circuit for reproducing a DC component of the picturesignal, a synch separation circuit for separating a synchronizing signalfrom the picture signal, a vertical synch separation circuit forseparating a vertical synchronizing signal from the synchronizingsignal, a phase locked loop circuit for separating a horizontalsynchronizing signal from the synchronizing signal and generating a highfrequency clock signal that is phase-locked at an integral multiple ofthe horizontal scanning interval, a memory for reading writing theentered control signals, a level conversion circuit for converting thelevel of the entered control signals, a superimposing circuit connectedto an output of said clamp circuit and an output of said levelconversion circuit, for superimposing the entered control signal on thepicture signal, and a timing generator for generating based on thevertical and horizontal synchronizing signals and the high frequencyclock signal a memory control signal for said memory and a superimposetiming signal for said superimposing circuit.